A saturated liquid feed of 1000 kmol/h consists of 25 mol% propane, 35 mol% n-butaneand 40 mol% n-hexane. A distillate recovery of 99 mol% n-butane and bottoms recovery of 98

mol% n-hexane isdesired. \alpha_{\text {hexane-butane }}=0.2 Constant molar overflow (CMO) is valid. Reflux is returned as a saturated liquid. Thecolumn has a partial reboiler and a total condenser. \text { Using Gilliland correlation, calculate the total number of stages if } R=1.025 \times R_{\min -} \text { The average relative volatility is } \alpha_{\text {propane }-\text { butane }}=2.04 \alpha_{\text {butane }-\text { butane }}=1.00 \mathrm{and}